I've used the Summit Viper for 5 years and have to complain about it. It's the most comfortable stand I've ever used. The only complaint I have is it is so bulky when strapped to your back. It extends over 2 feet from your back. It's a pain when walking through thick brush or on long treks into the woods.

I finally broke down and bought a LW Sit and Climb after hearing so much about it. It packs flat and it a bit lighter than the Viper. The seat isn't nearly as comfortable as the Viper, but I fixed that by taking the Vipers off and putting it on the LW. Now I have the best of both worlds!